Conventionally disclosed is a wire rope flaw detector which uses a detection coil to detect leakage magnetic flux generated from a damaged portion, such as disconnection of a component wire, of a wire rope in a magnetic saturated state, whereby the damaged portion of the wire rope is detected (e.g., see patent document 1).
Further, conventionally, in a magnetic flaw detector for wire rope including: an excitation core which has at least two magnetic poles being disposed so as to adjacently face a wire rope and; exciting coils wound around the excitation core; an electric power for supplying a current to the exciting coils; and detection coils disposed between the two magnetic poles to cause polarized magnetic flux to pass through there inside, the polarized magnetic flux having branched off from main magnetic flux passing inside the wire rope through the two magnetic poles, when the wire rope is displaced in its longitudinal direction relative to the excitation core, an electromotive force is excited in the detection coil, whereby mechanical damage on a surface of the wire rope is detected. The magnetic flaw detector characteristically uses an AC electric power as the electric power (e.g., see patent document 2).    [Patent document 1] Japanese Laid-Open Patent Publication No. H09-210968 (Paragraph [0003], FIG. 8, and the like)    [Patent document 2] Japanese Laid-Open Patent Publication No. H11-230945 (claim 1, FIG. 1, and the like)